1. How has Antarctica changed over the years?
This is a great question, and one I’ll answer first. To understand Antarctica, you have think very
long term. Continents are all found on
massive plates that move over the mantle of the Earth. The US and Europe are moving away from each
other at about a ½ inch a year, as the mid-atlantic ridge grows. On the other side, the Pacific is slowly
subducting, and in a few million years, trips to Japan will be a little shorter
than they are now. Antarctica used to be connected to other landmasses in a
supercontinent called Gondwana. About 50
million years ago, Australia and Antarctica split apart and Antarctica drifted
south. All plants and animals left on Antarctica
eventually died, but we still find fossil records of plants that existed
millions of years ago.
As Antarctica moved south, ice began to develop as ocean
waters cooled, and the continent started to resemble what it is today. By 15
million years ago, Antarctica was covered in ice and snow. So much in fact, that it weighs down and
depresses the entire continent by as much as half a mile!
2. What is the range of temperatures in Antarctica? How is
the weather during the summer?
Because it is summer here right now in the southern hemisphere
it is relatively warm for Antarctica. I
looked up the current temperature here and it is 30F with 6mph winds, so not
worse than an average January day in NYC really. South Pole station, because it
is much farther from the ocean, further south still, and at a much higher altitude,
is much colder however. It is currently -17F, -27F with wind chill there, and
that is almost as warm as it gets there. For the most part the summers are relatively
mild on the coast where we are, much like a New England winter. The interior of the continent is much colder
in general. And in the winter, when it’s
dark 24 hours a day, everything is cold.
The coldest temperature ever recorded on earth was at Vostok Station (a Russian
station) was −128.6 °F on July 21, 1983. Brrrrrrr.
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| You can see average temperatures at a few Antarctic stations, as well as New York, London, and Sydney. Notice how New York and London seasonal changes are reversed from Antarctica and Sydney. |
3. Does the ice ever crack near you? And why does it crack?
Oh yes, all the time.
By ice though, I’m talking about sea ice. There is, of course, many millions of
kilometers of land ice out here, but that stuff is far more stable. The sea ice, on the other hand, actually
breaks, floats away, melts, and reforms in large sections every year. When we
drive our vehicles over the ice, we have to always be on the lookout for ice
cracks. Under snow, it can look very small, but a crack could be several feet
wide at the base, and you don’t want to drive right into the water! It is always a bit weird to remember that I’m
not on land when we drive to our field sites, I’m over hundreds of feet or more
of seawater. The cracking occurs every
year in the summer months due to a couple of factors. First and most
importantly is temperature - as the ice warms it melts a little bit. This causes a weak spot to form. And because it is made from seawater, the ice
isn’t as strong as land ice, due to the salt. Another factor is the influence
of tidal shifts. As the ocean underneath
flows back and forth, it creates pressure against the ice. If the ice has been weakened by melting, it
may crack. This crack may continue to
grow, or if it gets colder “heal up” and reform with new ice.
What you are seeing here is a pressure ridge, caused by the transition of sea ice to land ice right where the land meets the sound. They are beautiful formations, but they can be very dangerous to try to cross with vehicles.
4. What types of animals have you seen up close?
I have gotten to see a lot of marine invertebrates – including
the sea urchins we work on, and the super cool sea spiders! Also, I have gotten
to hang out with some fish with antifreeze proteins in their blood. They have this because they live in seawater
that is below the freezing temp for fresh water, and if they didn’t have
antifreeze, their blood could freeze inside them! And as for larger animals, I’ve
seen a number of Weddell Seals near sea ice cracks, as well as in our research
ice holes, and of course my favorite, Emperor Penguins! They are really amazing animals!
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| Seal, hanging out by a sea ice crack |
This penguin knows how good it looks. Show off.
5. Do you hear the seals calling under the ice? How do the
seals survive in that kind of weather?
Unfortunately, I haven’t had a chance to hear any of them, since
I haven’t been out on the ice with recording equipment on a quiet day. I know the scene from the movie you are
referring to, and it is an amazing sound.
If I get a chance, I will ask one of the divers here if they’ve
experienced the Weddell Seal sounds underwater, and get back to you. As for how they survive out here in this weather, that's a great question - in fact it's a question that scientists are currently studying right now! They are using infrared heat sensing cameras to understand how a seal maintains it's internal body temperature when the outside temperature is downright bitter cold. What we know is that they have a huge layer of blubber - fat - that helps insulate them in the very chilly water and sometimes even colder air. They have evolved to be as round as possible, because the less of their body that is exposed to the cold, the warmer their core can be. Also, they can keep blood from flowing to their extremities when they're diving, conserving as much heat as possible in their chest and body.
That is a fat and happy Weddell seal. We named him Rusty.
6. Is Frosty Boy good?
I had Frosty Boy yesterday!
And yes, it’s delicious. It is
the best soft-serve ice cream I’ve had. I’ve tried vanilla, butterscotch,
mocha, cinnamon, and mint tea. I do NOT
recommend mint tea – it tastes like a mouthful of frozen tooth paste. However, the rest are all delicious, and they
go great with the other wonderful deserts found here occasionally – like chocolate
chip cookies or pumpkin pie. Also, for
the ladies, the South Pole Station has a machine they’ve called Frosty
Girl.
